Re: [PATCH 04/11] drm/r128: Fix undefined behavior due to shift overflowing the constant

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Jun 16, 2022 at 09:06:45AM -0700, Randy Dunlap wrote:
> 
> 
> On 5/19/22 06:05, Daniel Vetter wrote:
> > On Mon, Apr 25, 2022 at 11:46:53AM -0700, Randy Dunlap wrote:
> >>
> >>
> >> On 4/5/22 08:15, Borislav Petkov wrote:
> >>> From: Borislav Petkov <bp@suse.de>
> >>>
> >>> Fix:
> >>>
> >>>   drivers/gpu/drm/r128/r128_cce.c: In function ‘r128_do_init_cce’:
> >>>   drivers/gpu/drm/r128/r128_cce.c:417:2: error: case label does not reduce to an integer constant
> >>>     case R128_PM4_64BM_64VCBM_64INDBM:
> >>>     ^~~~
> >>>   drivers/gpu/drm/r128/r128_cce.c:418:2: error: case label does not reduce to an integer constant
> >>>     case R128_PM4_64PIO_64VCPIO_64INDPIO:
> >>>     ^~~~
> >>>
> >>> See https://lore.kernel.org/r/YkwQ6%2BtIH8GQpuct@zn.tnic for the gory
> >>> details as to why it triggers with older gccs only.
> >>>
> >>> Signed-off-by: Borislav Petkov <bp@suse.de>
> >>> Cc: David Airlie <airlied@linux.ie>
> >>> Cc: Daniel Vetter <daniel@ffwll.ch>
> >>> Cc: Alex Deucher <alexander.deucher@amd.com>
> >>> Cc: dri-devel@lists.freedesktop.org
> >>
> >> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
> > 
> > Pushed to drm-misc-next, thanks for patch&review.
> > -Daniel
> > 
> 
> Hi,
> 
> Will this be merged to mainline any time soonish?

It missed the merge window by a hair, so it's in linux-next and will get
into the next one.
-Daniel

> 
> thanks.
> 
> >>
> >> Thanks.
> >>
> >>> ---
> >>>  drivers/gpu/drm/r128/r128_drv.h | 4 ++--
> >>>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/r128/r128_drv.h b/drivers/gpu/drm/r128/r128_drv.h
> >>> index 2e1bc01aa5c9..970e192b0d51 100644
> >>> --- a/drivers/gpu/drm/r128/r128_drv.h
> >>> +++ b/drivers/gpu/drm/r128/r128_drv.h
> >>> @@ -300,8 +300,8 @@ extern long r128_compat_ioctl(struct file *filp, unsigned int cmd,
> >>>  #	define R128_PM4_64PIO_128INDBM		(5  << 28)
> >>>  #	define R128_PM4_64BM_128INDBM		(6  << 28)
> >>>  #	define R128_PM4_64PIO_64VCBM_64INDBM	(7  << 28)
> >>> -#	define R128_PM4_64BM_64VCBM_64INDBM	(8  << 28)
> >>> -#	define R128_PM4_64PIO_64VCPIO_64INDPIO	(15 << 28)
> >>> +#	define R128_PM4_64BM_64VCBM_64INDBM	(8U  << 28)
> >>> +#	define R128_PM4_64PIO_64VCPIO_64INDPIO	(15U << 28)
> >>>  #	define R128_PM4_BUFFER_CNTL_NOUPDATE	(1  << 27)
> >>>  
> >>>  #define R128_PM4_BUFFER_WM_CNTL		0x0708
> >>
> >> -- 
> >> ~Randy
> > 
> 
> -- 
> ~Randy

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch